c# – HttpContext.Current.Session为null

我有一个WebSite与一个类库中的一个自定义Cache对象.所有的项目都在运行.NET 3.5.
我想将此类转换为使用Session状态而不是缓存,以便在应用程序回收时保留stateerver中的状态.
但是,当我访问我的Global.asax文件中的方法时,这个代码会引发异常“HttpContext.Current.Session is null”.我打电话给这个类：

Customer customer = CustomerCache.Instance.GetCustomer(authTicket.UserData);

为什么对象allways空？

public class CustomerCache: System.Web.SessionState.IRequiresSessionState
{
    private static CustomerCache m_instance;

    private static Cache m_cache = HttpContext.Current.Cache;

    private CustomerCache()
    {
    }

    public static CustomerCache Instance
    {
        get
        {
            if ( m_instance == null )
                m_instance = new CustomerCache();

            return m_instance;
        }
    }

    public void AddCustomer( string key,Customer customer )
    {
        HttpContext.Current.Session[key] = customer;

        m_cache.Insert( key,customer,null,Cache.NoAbsoluteExpiration,new TimeSpan( 0,20,0 ),CacheItemPriority.NotRemovable,null );
    }

    public Customer GetCustomer( string key )
    {
        object test = HttpContext.Current.Session[ key ];

        return m_cache[ key ] as Customer;
    }
}

你可以看到我已经尝试添加IRequiresSessionState到类,但没有什么不同.

干杯
延

using System.Web.SessionState;

// ...

protected void Application_PreRequestHandlerExecute(object sender,EventArgs e)
    {
        if (Context.Handler is IRequiresSessionState || Context.Handler is IReadOnlySessionState)
        {
            HttpContext context = HttpContext.Current;
            // Your Methods
        }
    }